Bumping this up just for a little bit.
I've been looking through videos on beta maps, specifically that garage where you lower an engine into an APC. The texture I've seen looks like the prototype texture, but I'm not sure if it's official or a remake. Lots of texture remakes for the beta.
From my knowledge, this old texture isn't documented anywhere. So I can't really fact check.
Anyway again, regardless if it's official or a custom reskin, I'd still like to get my hands on it.